单选题 Earthquake damage has caused some of the communications networks to shut down ______ until essential repairs are carried out.

【正确答案】 B
【答案解析】shut down是表示“中断或停止经营”的不及物动词词组，且until essential repairs are carried out是状语从句，因此横线处应填入修饰动词的副词。答案是(B)completely。